Researchers identify species and areas most vulnerable to spread of infection
A skua, a predatory seabird of the Antarctic region. They have been primarily affected by the bird flu outbreak. Photo: iStock Scientists have detected the presence of avian flu for the first time in the Antarctic region, raising concerns for remote populations of penguins and seals.
The findings by researchers from the British Antarctic Survey (BAS) followed reports of several “potentially symptomatic birds and unexplained mortality” and further tests confirmed the presence of Highly Pathogenic Avian Influence (HPAI).
The HPAI was detected in brown skua (a predatory seabird) populations on Bird Island, South Georgia, making it the first known case in the Antarctic region.
The researchers, in their findings presented in Biological Risk Assessment of Highly Pathogenic Avian Influenza in the Southern Ocean, said the malaise had possibly reached the region from South America.
Based on trends observed in Europe, North America and South Africa, scientists fear HPAI may lead to a decline in the breeding populations of vulnerable fragile wildlife residing in the region.
The viral disease HPIA or avian influenza, especially the H5 and H7 strains, mostly affects birds. These strains are highly pathogenic and have been reported in domestic poultry, resulting in high mortality if they manage to reach wild bird populations.
The virus is known to spread among birds and mammals due to predators and scavengers feeding on infected birds. In recent cases, marine mammals have also been found to be infected.
The ongoing outbreak of HPAI H5N1 was first reported in 2022. The scientists stated in the report that in July 2022, outbreaks were reported in the Northern Hemisphere’s wildlife, especially seabirds. This heightened fears that the pestilence might spread to Southern Ocean seabird populations as well.
In 2022 and 2023, HPAI H5N1 spread rapidly in South America. Fears regarding southern birds came true when a team from the Antarctic Wildlife Health Network investigated and found the infection had spread in the Antarctic and sub-Antarctic region.
Last year, the virus spread along the Pacific coast of South America, affecting populations in Peru and Chile. It travelled 6,000 kilometres towards the continent’s southernmost tip — Tierra del Fuego — in three months, impacting 500,000 seabirds. It also caused significant outbreaks in marine mammals, leading to the deaths of 20,000 South American sea lions.
A press statement by BAS stated:
BAS and Government of South Georgia & the South Sandwich Islands (GSGSSI) remain vigilant for further cases and science and visitor programmes are currently continuing under enhanced biosecurity measures.
It added that BAS is working in close partnership with the GSGSSI, guided by their tiered response plan to monitor and manage the outbreak.
According to the researchers’ risk assessment, the most threatened avian group are gulls and skuas. They are followed by birds of prey such as hawks and caracaras, terns and shorebirds.
Among marine mammals, fur seals and sea lions are reportedly most vulnerable, followed by southern elephant seals and dolphins.
The researchers also found that, “sub-Antarctic slands between southernmost tip of South America and the Antarctic Peninsula with the Falkland Islands are at most risk.” The risks are significantly high due to the presence of other vulnerable wildlife groups.
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